feat: 添加知识库检索功能和改进模型路由错误处理

- 在ChatRequest中添加Citation事件类型，支持引用来源展示
- 实现聊天上下文准备服务，构建带源元数据的受限聊天上下文
- 添加ThreadedProcess类以支持Windows平台的子进程操作
- 改进检索引擎中的错误处理和向量搜索逻辑
- 实现严格的嵌入模型验证和索引重建机制
- 添加前端聊天界面的知识库检索开关
- 实现搜索历史记录功能和错误降级处理
- 更新模型路由设置提示信息以反映索引重建需求

frontend/src/stores/search.ts

@@ -5,10 +5,19 @@ import * as searchService from '@/services/searchService'
 import { ApiErrorClass } from '@/services/apiClient'
 
 const VECTOR_ERROR_CODES = new Set([
+  'SEMANTIC_INDEX_UNAVAILABLE',
   'VECTOR_UNAVAILABLE', 'EMBEDDING_UNAVAILABLE', 'INDEX_UNAVAILABLE',
   'MODEL_NOT_FOUND', 'MODEL_CAPABILITY_MISMATCH', 'PROVIDER_UNAVAILABLE',
 ])
 
+const HISTORY_KEY = 'notes-agent.search-history.v1'
+function readHistory(): string[] {
+  try {
+    const value: unknown = JSON.parse(localStorage.getItem(HISTORY_KEY) ?? '[]')
+    return Array.isArray(value) ? [...new Set(value.filter((item): item is string => typeof item === 'string').map(item => item.trim()).filter(Boolean))].slice(0, 10) : []
+  } catch { return [] }
+}
+
 export const useSearchStore = defineStore('search', () => {
   const query = ref('')
   const mode = ref<'fts' | 'vector' | 'hybrid'>('hybrid')
@@ -16,11 +25,23 @@ export const useSearchStore = defineStore('search', () => {
   const total = ref(0)
   const isSearching = ref(false)
   const selectedIndex = ref(0)
-  const recentQueries = ref<string[]>(['红黑树', '死锁', 'TCP三次握手'])
+  const recentQueries = ref<string[]>(readHistory())
+  const historyError = ref('')
+  let searchVersion = 0
+  function persistHistory() {
+    try { localStorage.setItem(HISTORY_KEY, JSON.stringify(recentQueries.value)); historyError.value = '' }
+    catch { historyError.value = '浏览器无法保存搜索记录，本次记录仅保留到页面关闭。' }
+  }
+  function clearHistory() { recentQueries.value = []; persistHistory() }
   const error = ref<string | null>(null)
   const vectorUnavailable = ref(false)
 
   async function doSearch(request: SearchRequest) {
+    request = { ...request, query: request.query.trim() }
+    if (!request.query) return
+    const version = ++searchVersion
+    recentQueries.value = [request.query, ...recentQueries.value.filter(item => item !== request.query)].slice(0, 10)
+    persistHistory()
     query.value = request.query
     mode.value = request.mode || 'hybrid'
     isSearching.value = true
@@ -29,20 +50,24 @@ export const useSearchStore = defineStore('search', () => {
 
     try {
       const resp = await searchService.search(request)
+      if (version !== searchVersion) return
       results.value = resp.results
       total.value = resp.total
       selectedIndex.value = 0
     } catch (reason) {
+      if (version !== searchVersion) return
       const canFallback = mode.value !== 'fts' && reason instanceof ApiErrorClass && VECTOR_ERROR_CODES.has(reason.code)
       if (canFallback) {
         try {
           const fallback = await searchService.search({ ...request, mode: 'fts' })
+          if (version !== searchVersion) return
           results.value = fallback.results
           total.value = fallback.total
           mode.value = 'fts'
           vectorUnavailable.value = true
           selectedIndex.value = 0
         } catch (fallbackError) {
+          if (version !== searchVersion) return
           error.value = fallbackError instanceof Error ? fallbackError.message : '全文检索降级失败'
           results.value = []
           total.value = 0
@@ -53,16 +78,14 @@ export const useSearchStore = defineStore('search', () => {
         total.value = 0
       }
     } finally {
-      isSearching.value = false
+      if (version === searchVersion) isSearching.value = false
     }
 
-    if (request.query && !recentQueries.value.includes(request.query)) {
-      recentQueries.value.unshift(request.query)
-      if (recentQueries.value.length > 10) recentQueries.value.pop()
-    }
   }
 
   function clearResults() {
+    searchVersion++
+    isSearching.value = false
     results.value = []
     query.value = ''
     total.value = 0
@@ -90,6 +113,8 @@ export const useSearchStore = defineStore('search', () => {
     isSearching,
     selectedIndex,
     recentQueries,
+    historyError,
+    clearHistory,
     error,
     vectorUnavailable,
     doSearch,